THE SCIENTIFIC METHOD
1OBSERVATION
2 QUESTION
3 HYPOTHESIS
4 EXPERIMENT
5 ANALYSIS
6 CONCLUSION
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HYPOTHESES
- 1 Prove that we can create a back support that increases disc space and reduces disc pressure.
- 2 Prove that we can create a chair that is capable of improving your posture over time.
- 3 Prove that we can create the world’s most comfortable, lowest pressure cushion.
EXPERIMENT
Seating Expertise
Digital 3D Human Modeling+ Simulation Software
Medically-graded International Testing Standards
Submission to FDA as orthotic Device
Existing Data on the Science of Sitting
What We used to prove our hypotheses
EXPERIMENT
- Seating Expertise
- Digital 3D Human Modeling+ Simulation Software
- Medically-graded International Testing Standards
- Submission to FDA as orthotic Device
- Existing Data on the Science of Sitting
HYPOTHESIS
Prove that we can create a back support that increases disc space and reduces disc pressure
Experiment
Based on 20+ years of designing seating products for wheelchair riders, Anthros imagined an independently adjustable 2 part back system.
Experiment
Experiment
It was designed using expertise of the human body and a deep understanding of sitting biomechanics.
Experiment
According to existing research and experience, we knew that supporting the pelvis in neutral was key to supporting an upright spine with optimal curves and disc space.
Experiment
We began by building models and testing on human models of various shapes and sizes.
Experiment
There were multiple iterations to determine and optimize pivot points and contours of the adjustable 2-part back system to achieve our hypothesis.
Experiment
We based our testing relative to the Wilke et alstudy which studied the intervertebral pressure of a live person in different positions. They used a pressure transducer that was inserted in the disc at L4-5.
Experiment
Based on decades of designing medical seating products for wheelchair users, Anthros imagined an independently adjustable two-part back system to better support and fit the vast differences in human bodies. It was designed using a meta analysis of sitting research and a deep understanding of sitting biomechanical principles.
Experiment
Based on clinical research and decades of experience in medical seating design, we identified that aligning and supporting the pelvis, sacrum, and L4 and L5 regions is crucial for establishing a natural lumbar curve. This alignment promotes equal disc spacing throughout the spine. To achieve this, we used advanced 3D human modeling to validate and refine our two-part back design. After perfecting the design in a virtual environment, we created prototypes and tested them on human subjects of various shapes and sizes to confirm our findings.
Experiment
Years of design iterations were dedicated to determining and optimizing the pivot points, movement patterns, and foam shapes of our two-part back system. This extensive work resulted in the development of the most natural human fitment available in any back seating system. It meets the diverse shapes, comfort, and support needs of our extensive panel of human test subjects.
The effectiveness of this two-part back system was validated using 3D human modeling. Our testing was based on the Wilke et al. study, which examined intervertebral pressure in a live person in various positions. In their study, they used a pressure transducer inserted into the L4-5 disc.
Biomechanical and tissue modeling performed by Simuserv integrated by Abaqus Unified FEA from Dassault Systèmes
We leveraged cutting-edge 3D human modeling software and collaborated with the esteemed Simuserv Human Modeling team for all our human modeling design and analysis. Simuserv confirmed that disc pressure at L4-5 decreases with the properly adjusted Anthros two-part back system. Additionally, Simuserv observed a significant reduction in L4-5 disc pressures when our two-part back system was used alongside the Anthros tilt feature.
Analysis
The results of the Wilke study showed that an optimal disc pressure in neutral standing is 0.5 mpa.
With the 0.5 mpa value as optimal, we were pleased to see that our two-part back system could achieve and even surpass these values.
| Standard Office Chair | Standing | Anthros Upright | Anthros Tilt |
|---|---|---|---|
| 0.7 mpa | 0.5 mpa | 0.5 mpa | 0.3 mpa |
| Standard Office Chair | Standing |
|---|---|
| 0.7 mpa | 0.5 mpa |
| Anthros Upright | Anthros Tilt |
| 0.5 mpa | 0.3 mpa |
Conclusion
We were able to show that our two-part back system reduces disc pressure and the reduction of intervertebral disc pressure is correlated to decreased back pain according to research. And the absence of pain can be associated with comfort.
HYPOTHESIS
Prove that we can create a chair that improves posture
Experiment
Using 3D human modeling, we wanted to see the effect of supporting the pelvis independently in neutral. The goal was to see the spine follow into an “S” curve, which is a healthy anatomical posture for the intervertebral discs, vertebra, and nerve roots.
Analysis
Existing research shows that supporting the pelvis is the key to achieving and maintaining optimal spinal curves.
Existing research also shows that the body adapts to the position it is in most frequently. This means that sitting poorly all day will result in muscle imbalances and poor posture over time; whereas sitting well all day can help restore muscle balance and improve posture over time.
Conclusion
It can be clearly seen in the human modeling simulation that supporting the pelvis with the low back support resulted in the spine elongating and moving into an “S” curve. The upper back support acts to support the upper spine in this position. We can therefore infer, that sitting in the Anthros chair daily will position the body optimally and improve posture over time.
The FDA further validated our hypothesis by registering the Anthros chair as an orthotic device #3021484401, which is used to improve posture.
In legal terms: orthodic device means an apparatus used to support, align, prevent, or correct deformities, or to improve the function of movable parts of the body.
HYPOTHESIS
Prove that we can create the world’s most comfortable, lowest-pressure cushion
Experiment: Stages of design
With 70+ years designing wheelchair seat cushions, the knowledge and expertise of caring for the most vulnerable sitting population was brought to the Anthros seat cushion. The design began using anthropometric data, then 3D human simulation was used to adjust the design to achieve the lowest peak pressures possible. It began with contours to match the human shape, but we believed we could get lower pressures than we were seeing. We then created empty pressure relief cutouts in the area under the sit bones and saw a drastic reduction of peak pressures. These domes were then perfected in shape and size to ensure that different shapes and sizes of subjects would experience the same benefits.
2" Flat Foam
Contoured Foam
Contoured Foam with Pressure - Relieving Domes
Stages of Design
2” FLAT FOAM
CONTOURED FOAM
CONTOURED FOAM WITH PRESSURE-RELIEVING DOMES
Experiment
Once we optimized the cushion design using 3D Human modeling to have the lowest sitting pressures (softness), we then validated the virtual design using real foam prototypes at an accredited university. The International Organization for Standardization (ISO) develops standards for all types of products, including wheelchair seat cushions. These standardized tests are established to evaluate how a product performs on measures that impact the user of the product. Anthros chose the University of Pittsburgh School of Health and Rehabilitation Sciences to perform the standardized bench tests on 10 office chair seats to evaluate performance, considering most people sit in these seats for at least 8hrs per day. Since the walking population primarily uses office chairs we focused on the three known measures of perceived tissue comfort based on existing and extensive research: peak sitting pressures, cushion contact area, and tissue shear strain seen from sliding on the cushion.
*Performed on 6/8/22 at the University of Pittsburgh with a rigid load indenter. Human results may vary.
SHEAR Shear is the combination of downward pressure (in sitting, through the buttocks), and horizontal friction (sliding forward in your seat when your skin sticks to the seat and you feel that pull). Imagine a child sliding down a metal slide wearing a bathing suit, with skin sticking to the slide all the way down; this is shear.
CONTACT AREA Contact area represents how much contact the indenter (or person) is making with the seat surface. A higher contact area is desired as it implies greater pressure distribution and lower peak pressures.
= Comfort
PEAK PRESSURE INDEX
Peak pressure implies high pressures in one area. The peak pressure index is what is calculated by averaging the individual sensor results along the simulated IT (sit bones) portion of the testing fixture. Rather than simply taking the single highest value as the peak pressure, one random reading won’t skew the results or the perception of performance. A high peak pressure index is associated with discomfort or pain, so low values are desired.
Analysis
The results of the independent university testing clearly show that the Anthros seat cushion outperforms all other office and gaming chair seat cushions tested—in each measure of comfort.
Shear
The first test is for shear strain. This simulates the pain one might feel when slouching and sliding off of their seat surface. The higher the shear force number the more one might be able to sense pain over time.
Pressure Distribution/ Contact Area
The second test is for the cushion contact area. This indicates the amount of tissue from the back of your leg and buttocks that will immerse into the cushion to help reduce sitting pressures. A park bench would have a low number while a large down feather pillow might have a higher number. You can guess which number might lead to greater comfort.
Peak Pressure Index
The third test is to record the sitting pressure your body will make with the various seat designs. Again, think park bench versus a large down feather pillow.
Conclusion
Independent university testing proves that Anthros outperforms industry-leading office chairs in measures of comfort. Anthros has created the most comfortable sitting experience with the lowest peak pressures.
DON’T JUST TAKE OUR WORD FOR IT
SEE WHAT SIMUSERV MANAGING DIRECTOR ALEXANDER SIEFERT HAS TO SAY ABOUT ANTHROS
CONCLUSION
SUMMARY
After years of experiments, collecting data, and existing research, we found we COULD:
- 1 Prove that we can create a back support that increases disc space and reduces disc pressure
- 2 Prove that we can create a chair that improves posture
- 3 Prove that we can create the world’s most comfortable, lowest pressure cushion
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